Periconia delonicis

Periconia delonicis Jayasiri, E.B.G. Jones & K.D. Hyde, in Jayasiri et al., Mycosphere 10(1): 95

(2019)

Index Fungorum number: IF555562 Facesoffungi number:05268

Saprobic on a dead leaf of Musa sp. Sexual morph: Undetermined. Asexual morph: hyphomycetous. Conidiophores 320−400 × 8−12 μm (x̄ = 365 × 9.5 μm, n = 10) macronematous, rarely micronematous. Macronematous conidiophores and conidia resembled a stipe and a globular head. Stipe of the Conidiophores unbranched, straight or flexuous from the middle, septate, pale to dark brown, often appearing black, smooth, globular heads shining by reflected light. Conidiogenous cells 4−7.5 × 3.4−7.4 μm (x̄ = 5.5 × 5.3 μm, n = 15) monoblastic or polyblastic, discrete on the stipe, determinate, ellipsoidal, pale brown to brown. Conidia 4−8 × 4−6 μm (x̄ = 5.6 × 5.4 μm, n =15), catenate, in chains, arising at one or more points on the curved surface of the conidiogenous cell, simple, usually spherical or subspherical, pale to dark brown, smooth to minutely veruculose, aseptate.

Culture characteristics: Conidia germinated on PDA within 48 hrs, reaching 40 mm diam. in 2 weeks at 25°C. Colonies on PDA with sparse, pinkish white mycelia on the surface, circular and flattened. Surface is smooth, with small, brown granular–like, powdery masses at maturity. The reverse of the colony is dark brown and yellow in the center with a white margin. Conidia and conidiophores are not observed in mature colonies.

Material examined: THAILAND, Chiang Mai Province, Mae Taeng District, on a dead leaf of Musa sp. (Musaceae), 22 September 2018, B.C. Samarakoon, BNS012 (MFLU 20–0696), living culture MFLUCC 20–0235.

Notes: Based on BLASTn search results of SSU, LSU, ITS, TEF sequence data, our strain (MFLUCC 20−0235) showed high identity to the taxa in GenBank as follows; SSU = 99.75% similarity to Periconia palmicola (MFLUCC 14−0400), LSU = 99.88% similarity to P. delonicis (MFLUCC 17−2584), ITS = 99.20% similarity to P. palmicola (MFLUCC 14−0400). Multi–loci phylogenetic analysis (Fig. 1) showed that the new strain MFLUCC 20–0235 forms a clade together with P. palmicola (MFLUCC 14−0400) and P. verrucosa (MFLUCC 17−2158) with high statistical support (ML = 98%, BYPP = 1.00).

Our strain (MFLUCC 20–0235) shares similar morphology to the type of Periconia delonicis in having macronematous, unbranched conidiophores, with monoblastic, terminal conidiogenous cells and brown, globose to subglobose, aseptate, veruculose conidia (Jayasiri et al. 2019). Our strain (MFLUCC 20−0235) also shares similar size range of conidiophores (320−400 × 8−12 μm vs. 360−420 × 8−12 μm) and conidia (4−8 × 4−6 μm vs. 5.5−7 μm diam.). Based on recommendations by Jeewon & Hyde (2016), we also compare the nucleotide bases of TEF region for our new strain and the type strain of P. delonicis. MFLUCC 20−0235 differs from P. delonicis (MFLUCC 17−2584) in 5/746 bp (0.67%).

In our phylogenetic analyses, MFLUCC 20−0235 and ex–type stain of Periconia delonicis (MFLUCC 17−2584) showed a close phylogenetic affinity to P. palmicola (MFLUCC 14−0400) and P. verrucosa (MFLUCC 17−2158). The conidiophores, conidiogenous cells and the conidia of MFLUCC 20−0235 shares similar morphology with the holotype illustration of P. palmicola in Hyde et al. (2020a) (i.e. dark brown to black conidiophores, hyaline conidiogenous cells, subglobose to globose conidia). However, P. palmicola differs from MFLUCC 20−0235 in having comparatively short conidiophores (151–188 × 5.6–8 μm vs. 320−400 × 8−12 μm) which were branched at apex. The conidiophores of MFLUCC 20−0235 are unbranched and comparatively long with respect to P. palmicola. A nucleotide base pair comparison of TEF region showed that MFLUCC 20−0235 differs from P. palmicola (MFLUCC 14−0400) in 4/746 (0.53%). MFLUCC 20−0235 also has similar morphology to P. verrucosa (MFLUCC 17−2158) but differs in having longer conidiophores (320−400 × 8−12 μm vs. 170–296 × 10–12 μm) and smaller conidia (4−8 × 4−6 μm. vs. 7–15 μm diam.) (Phukhamsakda et al. 2020). A nucleotide base comparison of ITS and TEF regions showed that MFLUCC 20−0235 differs from P. verrucosa (MFLUCC 17−2158) in 7/501 bp (1.39%) of ITS and 4/746 bp (0.53%) of TEF. Based on morphological comparison with the types of P. delonicis, P. palmicola and P. verrucosa, a nucleotide base comparison of ITS and TEF regions and phylogenetic evidence, we thus identify our new collection as P. delonicis. In this study, we report P. delonicis on Musa sp. (Musaceae, monocotyledon) for the first time.

Figure 1.    Maximum likelihood tree revealed by RAxML from an analysis of a concatenated SSU, LSU, ITS and TEF sequence dataset of the species in Periconiaceae, showing the phylogenetic position of Periconia delonicis (MFLUCC 20–0235) and P. cortaderiae (MFLUCC 20–0236). ML bootstrap supports (≥ 60%) and Bayesian posterior probabilities (≥ 0.95 BYPP) are given above the branches as ML/BYPP. The tree is rooted with Helminthosporium dalbergiae (MAFF 243853) and Massarina cisti (CBS 266.62). Strains generated in this study are indicated in red bold. Ex–type strains are indicated in black bold. The scale bar 0.02 represents the expected number of nucleotide substitutions per site.